A biomechanical model of human gait will be developed. This model wil be constructed as a multilinked open chain system whose motions will be governed by the principles of dynamics and kinematics in conjunction with known elements of the physiology an functional anatomy of gait. This model will be employed for the analysis of both normal and pathological gait. From this model the relative influence of both active muscular contraction and passive tissue constraints on the motion will be evaluated. In pathological gaits the response to a treatment modality will be evaluated by being able to analytically describe the mechanical response to this treatment and compare this to the actual patient response observed in the gait laboratory. In this way the effects of treatment and the mechanical compensatory mechanisms that arise secondary to this treatment may be evaluated.